Orthopedic implant rod reduction tool set and method

ABSTRACT

A tool set for implanting a rod in a human spine in conjunction with bone screws. The tool set includes a pair of end guide tools that receive opposite ends of the rod in channels and under manipulation by a surgeon facilitate transport of the rod toward the bone screws attached to the guide tools. Intermediate guide tools having guiding pass through slots are utilized to guide intermediate locations along the rod toward associated bone screws. An attachment structure operably connects the guide tools to the bone screws. The guide tools each include a lower guide and advancement structure to allow a closure top with mating structure to be rotated and driven downward against the rod and to cooperate with similar structure in the bone screw to seat and lock the rod therein. A method utilizing the tool set allows a surgeon to percutaneously implant the rod in the patient.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/220,185, filed Jul. 22, 2008, which is a Division of U.S. patentapplication Ser. No. 10/789,149, filed Feb. 27, 2004, which issued asU.S. Pat. No. 7,160,300 on Jan. 9, 2007, all of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to apparatuses and methods for use inperforming spinal surgery and, in particular, to tools and methods ofusing such tools, especially for percutaneously implanting a rod forspinal support and alignment using minimally invasive techniques.

For many years, spinal osteosynthesis apparatuses have been utilized tocorrect spinal deformities, injuries or disease. In such procedures,elongate rods are surgically attached to vertebrae of the spine toprovide support and/or to reposition certain vertebrae. Such rods aresecured to vertebrae utilizing bone screws and other implants.

Surgical techniques and bone screws have improved; however, in order toreduce the impact of such surgery on the patient, it has been desirablefor such implants to be inserted percutaneously or with surgicaltechniques that are minimally invasive to the body of the patient. Thispresents a problem with implantation of rods that are elongate and havehistorically required a long incision and open wound in order to providefor the length of the rod and the space required for the surgeon's handsto manipulate the rod, implants and insertion tools used with the rod.Consequently, it has been desirable to develop apparatuses andtechniques that allow for the insertion of bone screws, the insertionand reduction of a rod and the securing of the rod to the bone screwswith significantly reduced invasion into the body of the patient andwith minimal incision size in the skin over the operational site.

SUMMARY OF THE INVENTION

A set of tools is provided for percutaneously implanting a spinal rod ina patient. The tools include a pair of end guide tools that havechannels sized to receive opposite ends of such a rod and allow slidingof the rod along the channel so as to guide ends of the rod into opposedend bone screw-heads to which the end guide tools are attached.Intermediate guide tools are also attached to bone screw-heads betweenthe end bone screws and are slotted to guide the rod to respective bonescrews attached to the intermediate guide tools.

The guide tools also include lower attachment structure to allow theguide tools to be easily and quickly secured to mating structure on arespective bone screw-head, and to be easily removed from the bone screwby manual rotation of a handle of the tools exterior of the patient,after which the guide tool is withdrawn from the patient. Theintermediate guide tools have a snap-on and twist-off association withan associated intermediate bone screw and the end guide tools have atwist-on and twist-off association with respective end bone screws. Incertain embodiments, other attachment structure may be used.

Each of the guide tools also includes an internal first lower guide andadvancement structure that functions in cooperation with an internalsecond guide and advancement structure within the bone screw head andalso with external helical wound thread or locking flange form matingstructure on a bone screw closure top for closing the head of the bonescrew, so as to be able to load the closure top though a top-to-bottompassageway in the guide tool and rotate the closure top with a closuretop installation tool. Beneath the surface of the skin, the closure topis partially surrounded by the guide tool as it is directed to the bonescrew. Clockwise rotation of the closure top in the region of the lowerguide and advancement structure engages the closure top therewith andproduces mechanical advantage that causes the closure top to be drivenagainst the rod as it advances thereby urging the rod into the head of arespective bone screw. The closure top is driven and advanced byrotation of the closure top by the closure top installation tool andtransferred or passed from the first guide and advancement structure inthe guide tool to the second guide and advancement structure in the bonescrew without losing mechanical advantage and while continually applyingdownward pressure on the rod, so as to drive the closure top downwardand against the rod and so as to bias the rod into the head of the bonescrew where it is captured by the closure top and locked in position.

OBJECTS AND ADVANTAGES OF THE INVENTION

Therefore, the objects of the present invention are: to provide a set oftools for implanting a spinal rod for support or alignment along a humanspine with minimal surgical invasion of the patient; to provide such aset of tools including a pair of end tool guides for slidably guidingopposed ends of the rod toward end bone screws attached to the end guidetools; to provide such a set of tools including intermediate guide toolsfor each intermediate bone screw that guide the rod in slotstherethrough to respective bone screws; to provide such a set of toolsincluding rod pusher and closure top installation tools for assisting insecuring the rod in the bone screws; to provide such a set of toolswhere the end guide tools include a longitudinal channel extendingupwardly from near a bottom thereof to slidingly receive and guide endsof the rod toward associated end bone screws; to provide such a set oftools wherein the guide tools are easily attached to and disengaged fromthe bone screws; to provide such a set of tools wherein each guide toolincludes a first guide and advancement structure near the bottom thereofthat receives thread or locking flange mating structure on the closuretop and advances the closure top upon rotation of the closure top tourge the rod downwardly; to provide such a set of tools wherein theguide tool first guide and advancement structure acts cooperatively witha second guide and advancement structure on the bone screw so as totransfer the closure top upon rotation thereof from the guide tool tothe bone screw while continuously applying pressure to the rod andthereafter further advance the closure top to urge the rod into a seatedposition in the bone screw; to provide such a set of tools wherein theguide tools easily attach to and disengage from the bone screws bymanual manipulation of the surgeon outside the patient's skin; toprovide a method of implanting a rod into a patient with minimalsurgical invasion of the patient; to provide such a method utilizing thepreviously described tools for percutaneous implantation of such a rod;to provide such a method wherein end guide tools are utilized to receiveopposite ends of a rod and guide the rod ends in the guide tool channelsthrough manipulation of the guide tools and use of rod pusher tools; toprovide such a method wherein intermediate guide tools are utilized toguide intermediate locations along the rod to respective intermediatebone screws; to provide such a method wherein guide and advancementstructure near the bottoms of the guide tools, on the bone screws and onthe closure tops are utilized to pass the closure top under rotation andwith driving force between the guide tools and the bone screws and todrive the rod into a seating position in the bone screw; and to providesuch a set of tools and methods that are easy to use and especiallyadapted for the intended use thereof and wherein the tools arecomparatively inexpensive to produce.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention.

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary front elevational view of an intermediate guidetool in accordance with the present invention.

FIG. 2 is a fragmentary side elevational view of the intermediate guidetool.

FIG. 3 is a fragmentary cross sectional view of the intermediate guidetool, taken along line 3-3 of FIG. 1.

FIG. 4 is a fragmentary front elevational view of an end guide tool.

FIG. 5 is a fragmentary side elevational view of the end guide tool.

FIG. 6 is a cross sectional view of the end guide tool, taken along line6-6 of FIG. 4.

FIG. 7 is an enlarged and fragmentary front elevational view showingsnap-on installation of the intermediate guide tool on a polyaxial bonescrew head.

FIG. 8 is an enlarged and fragmentary front elevational view showing theintermediate guide tool installed on the bone screw head.

FIG. 9 is a fragmentary and cross-sectional view showing an early stageof the snap on installation of the intermediate guide tool on the bonescrew head.

FIG. 10 is a fragmentary and cross-sectional view showing a later stageof installation of the intermediate guide tool on the bone screw head.

FIG. 11 is a fragmentary and cross-sectional view showing theintermediate guide tool installed on the bone screw head.

FIG. 12 is a partial and generally schematic view of a patient's spinewith the end guide tool in conjunction with a bone screw installationtool, at the end of a process of installing a bone screw with attachedend guide tool in a spinal vertebra.

FIG. 13 is a partial and generally schematic view of the spine with apair of end guide tools and a pair of intermediate guide tools mountedon respective implanted bone screws and being utilized in an early stageof rod implantation to guide the rod toward the bone screws.

FIG. 14 is a view similar to FIG. 13 showing an intermediate stage ofguiding the rod toward the bone screws.

FIG. 15 is a view similar to FIG. 13 showing a later intermediate stageof guiding the rod toward the bone screws.

FIG. 16 is a partial and generally schematic cross sectional view of thespine showing rods being implanted on opposite sides of the spine andwith the rod on the left in an early stage of implanting while the rodon the right is in a later stage of implanting, taken along line 16-16of FIG. 15.

FIG. 17 is a cross-sectional view of an end guide tool, similar to FIG.6, shown during installation of the rod and a closure top in the bonescrew attached to the end guide tool.

FIG. 18 is a view similar to FIG. 17 showing the rod and closure topinstalled in the bone screw before final torquing of the closure top.

FIG. 19 is a partial and generally schematic side view of the spineshowing the rod fully installed in the bone screws.

FIG. 20 is an exploded and front elevational view of a closure topinstallation tool, antitorque tool and one of the intermediate guidetools attached to a bone screw.

FIG. 21 is a fragmentary and front elevational view of the antitorquetool being positioned so as to allow final torquing to a closure top inthe bone screw.

FIG. 22 is an enlarged and fragmentary side view of the end guide tool,as shown in FIG. 21, in conjunction with the installation tool andantitorque tool with portions broken away to shown interior detail andwith the closure top having just been installed and torqued in the bonescrew so that a break away head of the closure top has been removed.

FIG. 23 is a fragmentary and enlarged front elevational view showing anearly stage in the removal of the end guide tool from the bone screwwherein the tool has been rotated approximately ninety degrees relativeto its axis to the shown removal configuration from the installationconfiguration, such as seen in FIG. 17, thereof.

FIG. 24 is a fragmentary and enlarged front elevational view showing theend guide tool disengaged from the bone screw.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

The reference numeral 1 generally designates a tool set for use ininstalling an orthopedic spinal rod 4 into a set of bone screws 6 inaccordance with the present invention.

The tool set 1 of the illustrated embodiment includes a pair of endguide tools 9 and a plurality of intermediate guide tools 10, which inthe illustrated embodiment includes a pair of intermediate guide tools10 on each side of a patient's spine 17, but which can include none, oneor many intermediate guide tools 10 depending upon the particularapplication, so that one intermediate guide tool 10 is used for eachintermediate bone screw 6 to which the rod 4 is to be attached. The bonescrews 6 are implanted in the patent's spine 17 and, in particular, invertebrae 18 along the spine 17. Rods 4 are often installed on bothsides of the spine 17, as seen in FIG. 16, during the same procedure.

The end guide tool 9 is illustrated in FIGS. 4 through 6. In particular,each end guide tool 9 has an elongate body 14 that is sized and shapedto be sufficiently long to extend from implanted bone screws 6 throughan exterior of a patient's skin 14 so as to provide an outwardlyextending and upper handle portion 16 that allows and provides forgripping by a surgeon during procedures utilizing the tool set 1. Eachof the end guides 9 include an intermediate portion 19 and a lowerportion 20 along the length thereof. Each end guide tool 9 has a backwall 21 joining a pair of side walls 22 and 23.

More specifically, the upper portion 16 of each end guide tool 9 isgenerally channel shaped having a U-shaped cross-section, a C-shapedcross-section, a crescent shaped cross-section or the like in order toform an opening 24 that opens into and forms part of a channel 25 thatopens radially to one side of the end guide tool 9 and defines the sideto side opening 24 that is sufficiently wide to receive additional toolsand/or a closure top, as will be discussed below. The intermediateportion 19 of each end guide also includes an outward facing channel 29that has an opening 26 which is somewhat smaller than the opening 24 ofthe upper portion 16, such that the channel 29 is sized and shaped toreceive certain tools, as described below. Finally, the end guide lowerportion 20 also includes a groove or channel 34 opening radially outwardand having a side-to-side width or opening 35 that is approximately thesame size as the opening 26. The channel 34 has a rear web or wall 36having a lower end 37. All of the channels 25, 29 and 34 communicatewith one another and are aligned with one another so as to provide acontinuous elongate interior passageway with an open side from near atop 38 to near a bottom 39 thereof. This passageway provides acontinuous open path of non uniform cross-section radius from the top 38to the bottom 39 thereof that is parallel to an elongate axis A of eachend guide tool 9. As will be discussed later, each end guide toolchannel 34 is especially sized and shaped to slidingly receive arespective end 42 of the rod 4 therein.

Near the end guide bottom 39 is a cut out 45 wherein a portion of theback wall 21 of the channel 34 is removed in order to provide a regionhaving a size and shape to allow passage of a respective end 42 of therod 4 therethrough. Also located near the end guide bottom 39 is a rodabutment recess 49 that is sized and shaped for the purpose of bridgingthe rod 4 when the end guide tool 9 is rotated for removal, as describedbelow. The end guide tool 9 also receives a closure top 52, as will bedescribed below. Still further, near the bottom 39 of each of the endguides 9 is a helical wound first guide and advancement structure 50which may include conventional helical threads, helically wound squarethreads, or other guide and advancement structure to cooperate withequivalent or mateable structure within the bone screw heads 6 and onthe closure top 52, as also described below. The lower free ends of theside walls 22 and 23 form spaced tangs or legs 53 and 54.

At the bottom 39 of each end guide tool 9 is a radially inward facingattachment structure 55 that includes a base 56 and an upperly andaxially extending projection, flange or hook member 57 which will bedescribed in conjunction with a bone screw 6 below.

Referring more specifically to the bone screw 6, each of the bone screws6 includes a threaded shank 60 for screwing into and seating in avertebra 18 that is part of the human spine 17, see FIG. 12. Each of thebone screws 6 also include a head 66 with a rod receiving channel 67passing therethrough. Each of the bone screw shanks 60 includes an upperportion 70 that extends into the head 66 and is operationally securedtherein, so that the head 66 is rotatable on the shank 60 until lockedin position through engagement with the rod 4 under pressure. Inparticular, each shank upper portion 70 has an upwardly extending dome71 that engages the rod 4, when the rod 4 is placed within an associatedchannel 67 so that as the rod 4 urges the dome 71 downwardly, the shankupper portion 70 frictionally locks the shank 60 in position in a fixedangular position relative to the head 66. Many different conventionalbone screws where the head locks relative to the shank are well known inthe art.

The present invention is not intended to be restricted to a particulartype of bone screw. In the present embodiment, a polyaxial type bonescrew 6 is utilized wherein the shank 60 is locked in position by directcontact with the rod 4. It is foreseen that tool set 1 of the presentinvention can be used with virtually any type of bone screw, includingpolyaxial bone screws of many different types wherein the head is lockedrelative to the shank by structure other than in the manner described inthe illustrated embodiment.

Each bone screw head 66 has a pair of upstanding arms 74 and 75 withinternal second guide and advancement structure 76 on the insidesthereof. One of the arms 74 includes a circumferentionally locatedreceiver 78 that comprises a lower slot 79 that extends partiallycircumferentially about the periphery of the arm 74 and ends in anupperwardly projecting but hidden recess 80. While the slot 79 islocated on the arm 74 in the illustrated embodiment, a slot for thispurpose could be located anywhere on the bone screw head 66. The slot 79and recess 80 are sized, shaped and positioned so as to receive theattachment structure 55 of the end guides 9 therein. For greater detail,see the description below for the attachment structure associated withintermediate guide tools 10 and shown in FIGS. 10 and 11. The guide toolattachment structure 55 is sized and shaped to allow the attachmentstructure 55 to be received in the receiver 78 and locked therein bypulling the end guide tool 9 slightly axially upward relative to arespective bone screw 6. In order to disengage the guide tool 9 from thebone screw 6, the guide tool 9 is rotated 90 degrees counterclockwisefrom an attaching configuration, when viewing from the top so as todisengage the hook 57 from the recess 80 and so that the base 56 andhook 57 of the attachment structure 55 free to rotate above the rod 4and closure top 52 and be released from the receiver 78. In this manner,end guide tools 9 twist off of respective bone screws 6 and in theparticular illustrated embodiment the end guide tools 9 are alsoassembled on the bone screws 6 by the opposite twist on maneuver is thereverse of the twist off maneuver. In certain embodiments where there isenough flexibility in the legs 53 and 54, such that the legs 53 and 54can be splayed radially outwardly at the bottom 39 thereof in the mannershown in FIG. 7, so the end guide tool 9 snaps-on over the bone screw 6,as will be described for the intermediate guide tools 10 below.

The unflexed space between the legs 53 and 54 that is equivalent to thewidth of the opening 35 is preferably substantially equivalent to thespace between the bone screw arms 74 and 75 so that the channel 34 ofthe end guide tool 9 aligns with the channel 67 of the bone screw 6 whenthe end guide tool 9 is mounted on a respective bone screw 6. The recess49 is sized, shaped and positioned so that when the rod 4 is located inthe bone screws 6, the end guide tool 9 can rotate about axis A and therecess 49 allows the end guide tool 9 to straddle over the rod 4,thereby allowing the end guide tool 9 to twist relative to the bonescrew 6 and free the attachment structure 55 from the receiver 78 andthereafter be removed after all procedures are complete, as describedbelow.

Each of the intermediate guide tools 10 (see especially FIGS. 1 to 3)have a somewhat similar overall shape when compared to the end guidetools 9 in that both are preferably of the same axial length and widthand also have much structure in common; however with certain differencesas noted. Many of the structures of the intermediate guide tools 10 thatare the same as the end guide tools 9 are given the same referencenumber and the above noted description applies to each such tool 9 or10.

Each intermediate guide tool 10 has an overall elongate body 84 with anupper portion 86, an intermediate portion 87 and a lower portion 88. Inthe upper portion 86, the body 84 is generally C-shaped having aradially outward opening and elongate and axially extending channel 90terminating in a web or rear wall 91 with side walls 92 and 93. Thechannel 90 has a front opening 95 that extends parallel to an axis ofthe body 84 and that is sized and shaped to receive tools and elementsdescribed below.

The intermediate portion 87 also includes an outwardly opening channel97 with a rear web or wall 98 having a lower end 100 and a front opening99 that is not as wide as the opening 95. The lower portion 88 includestwo spaced side walls or legs 93 and 94 with an elongate and axiallyextending passthrough opening 101 between the legs 93 and 94 thatextends more than half way along the intermediate tool 10 and near theintermediate portion 87. The legs 93 and 94 define between them a passthrough and aligned slot 105 sized and shaped to slidingly receive therod 6.

The lower portion 88 extends substantially axially along theintermediate guide tools 10 and preferably to the location in use wherethe intermediate guide tools 10 pass through the skin 14.

The bottom 39 of each intermediate guide tool 10 includes a helicallywound but discontinuous square thread or first guide and advancementstructure 109 that cooperates with the closure top 52, as describedbelow. The lower end of each intermediate guide tool 10 also includes acutout 112 and an attachment structure 113 similar to structure 55 ofthe same type described for each end guide tool 9.

The attachment structure 113 (see especially FIGS. 9 to 11) includes abody 114 with an upperwardly extending, projection, flange or hookmember 115 that follows the inner curvature of the guide tool leg 93.The body 114 extends radially inward and is sized and shaped to matewith and set within the bone screw head receiver 78. The bone screwreceiver 78 is sufficiently wide to simultaneously receive both the body114 and hook member 115 in a radially inward direction, as is shown inthe view in FIG. 10. The attachment structure 113 is then set by axiallyraising the guide tool 10 relative to the bone screw 6 so at least partof the hook member 115 is located in the recess 80 which secures theguide tool 10 (likewise guide tool 9) to a respective bone screw 6, asseen in FIG. 11. This locks the guide tool 10 to a respective bone screw6 and prevents outward splaying of the leg 93. This is a snap-on typeinstallation or assembly as seen in FIG. 7 where the leg 93 splaysoutward during initial placement of the guide tool 10 over the bonescrew 6 and then returns to an unsplayed position when the attachmentstructure 113 seats in the receiver 78, as shown in FIG. 10.Alternatively, the guide tool 10 can be rotated approximately 90° aboutits axis A prior to joining with a respective bone screw 6, theattachment structure 113 lowered through the opening between the bonescrew arms 74 and 75 and aligned with the bone screw receiver 78, afterwhich the guide tool 10 is rotated back to the first position shown inFIG. 11 in a twist on type assembly. In some instances the guide tool 10is rotated somewhat more or less than ninety degrees to make thenecessary alignment for removal which depends on the specificconstruction of the parts.

Enclosure 52 closes between the spaced bone screw arms 74 and 75 tosecure the rod 4 in the channel 67. The closure top 52 can be any ofmany different plug type closures. Preferably the closure top 52 has acylindrical body 123 that has a helically wound mating guide andadvancement structure 125. The guide and advance at structure 125 can beof any type, including V-type threads, buttress threads, reverse anglethreads, or square threads. Preferably the guide and advancementstructure 125 is a helically wound flange form that interlocks with areciprocal flange form as part of the second guide and advancementstructure 76 on the interior of the bone screw arms 74 and 75. Asuitable locking guide and advancement structure of this type isdisclosed in U.S. Pat. No. 6,726,689 from Ser. No. 10/236,123 which isincorporated herein by reference. The helical wound guide 50 andadvancement structure in the bottom 39 of each of the guide tools 9 and10 is sized and shaped to receive the mating guide and advancementstructure 125 of the closure top 52 and align with the second guide andadvancement structure 76 of the bone screw 6 to form a generallycontinuous helically wound pathway, but does not require locking betweenthe closure top 52 and the tools 9 and 10, even when a locking flangeform is utilized on the closure top 52. The illustrated structure 125has a square form or a square thread type shape. The guide 50 allows theclosure top 52 to be rotated and the surgeon to develop mechanicaladvantage to urge or drive the rod 4, while still outside the bone screwhead 6, toward and into the bone screw head 66. This is especiallyhelpful where the rod 4 is bent relative to the location of the vertebra18 to which the rod 4 is to attach and is not easily placed in the bonescrew head 66 without force and the mechanical advantage provided by theguide 50. In particular, the first guide and advancement structure 109on each tool 9 and 10 is located and positioned to align with the secondguide and advancement structure 76 on the insides of the bone screw arms74 and 75, as seen in FIGS. 17 and 18 and pass the closure top 52therebetween while allowing the closure top 52 to continue to rotate andto continuously apply force to the rod 4, so as to seat the rod 4 in thebone screw head 66.

Each closure top 52 also preferably includes a break off head 127 thatbreaks from the body 123 in a break off region 128 upon the applicationof a preselected torque, such as 95 inch-pounds. The break off headpreferably has a hexagonal cross section faceted exterior 129 that isadapted to mate with a similarly shaped socket of a closure driving orinstallation tool 145, described below. It is foreseen that differentdriving heads or other methods of driving the closure top 52 can beutilize with certain embodiments of the invention.

Additional tools are utilized to assemble the implant. In particular,FIG. 16 illustrates a rod pusher 136 on the left. The pusher 136 has anelongate shaft or rod 138 that is preferably received in and passesthrough the interior of the guides 9 and 10, such as the channel 90 ofthe guide tool 10. The pusher 136 also has a tip 139 for engaging andurging the rod 4 downward, where there is minor resistance, and a handle141. It is foreseen that a pusher or gripper of the type that operatesoutside the guide tools 9 and 10 can be utilized, but is not preferredas such would normally require greater penetration of the skin 14 andmore invasion of the patient.

Shown in FIG. 16 on the left and in FIG. 17 is the closure installationtool 145. The tool 145 has an elongate rod or shaft 147 adapted to bereceived in and pass axially through any of the channels of the guides 9and 10 and a handle 149. The lower end of the rod 147 terminates in asocket 148 that is adapted to receive the closure break off head 127, asshown in FIG. 17.

Another tool used in implanting a rod 4 is an antitorque tool 153 whichis seen in FIGS. 20 to 22. The antitorque tool 153 is preferably usedwith the closure installation tool 145 to torque and set the closure top52, so it is snug against the rod 4, and thereafter break away the breakoff head 127 in the manner shown in FIG. 22. The antitorque tool 153includes a tubular hollow shaft 155 that is sized and shaped to beslidably received over the guide 9 and 10. The antitorque tool 153 has alower end 157 that has a pair of diametrically spaced bridges 158. Eachof the bridges 158 is sized and shaped to fit over the rod 4, as seen inFIG. 21. When in place, as seen in FIG. 21, the antitorque tool 153allows a surgeon to counter torque applied by the installation tool 145,when applying torque to and breaking away the break off head 127. Theantitorque tool 153 also has an upper handle 16 with an opening throughwhich the installation tool 145 passes in the manner suggested by thedashed lines in FIG. 20.

In use, the previously described tools are utilized to attach one ormore rods 4 to the human spinal column 17.

The procedure is begun by forming a relatively small incision, such asincision 165 in the skin 14 for each bone screw 6 to be used. Theincisions 165 are stretched into a round shape with a circumferenceequal to or just slightly larger than the guide tools 9 and 10. The skin14 is relatively flexible and allows the surgeon to move the incision165 around relative to the spine 17 to manipulate the various tools andimplants, as required. A drill (not shown) is utilized to form a guidebore (not shown) in a vertebra 18 under guidance of non invasive imagingtechniques, which procedure is well known and established. A thin pin166 is inserted in the guide bore. A bone screw 6 is selected inaccordance with the size of the patient's vertebra 18 and therequirements of the spinal support needed. Bone screws 6 having arotatable or poly axial head 66 are preferred for the procedure, as suchallow relatively easy adjustment of the rod 4 in the tools 9 and 10during placement and for movement of tools 9 and 10, as described below.The bone screw 6 is also cannulated so as to be receivable over andguided by the pin 166 toward the proper position in the associatedvertebra 18.

Before placing the bone screw 6 in the vertebra 18, the bone screw 6 ispreferably joined to an associated guide tool 9 or 10. This could bedone after insertion of the bone screw 6, but it is preferred toassemble both before inserting the bone screw 6. With respect to theintermediate guide tool 10, the lower end of the guide tool 10 issplayed or expanded outwardly by forcing the bone screw head 66 betweenthe legs 93 and 94, in the manner shown in FIG. 7 until the attachmentstructure 113 aligns with the receiver 78 and the former snaps into thelater, as shown in FIG. 8. Axial upward movement of the guide tool 10relative to the bone screw 6 then sets the attachment structure 113 inthe recess 80 in the process that is illustrated between FIGS. 10 and11. Alternatively, the tool 10 can be axially rotated ninety degreesrelative to the bone screw 6 and the attachment structure 113 alignedwith the recess 80 and then rotated back. The placement of the guidetools 9 on the associated bone screws 6 normally follows the later twiston procedure, as the structure of the guide tools 9 allow less flexingbecause of the longer back wall 21. With tool 9, the attachmentstructure 55 is placed in a respective receiver 55.

A series of bone screws 6 are installed in each vertebra 18 to beattached to the rod 4 by use of a screwdriver or installation tool 135,see FIG. 12, that has a head, designed to grip the particular bone screw6 used and which is also cannulated to receive the pin 166. For eachbone screw 6, an associated guide tool 9 or 10 extends through the skin14, as seen in FIG. 13. An end guide tool 9 is located at each end ofthe series of bone screws 6 and an intermediate guide tool 10 is locatedon each intermediate bone screw 6. The end guide tools 9 are turned orrotated so the channels 34 therein face one another and the intermediateguide tools 10 are aligned so slots 105 align with the channels 34.

The rod 4 is then inserted diagonally through one of the end skinincisions 165 in the manner shown in FIG. 13 so that a first rod end 42passes through the slots 105 in any intermediate guide tools 10 and intothe channel 34 of the opposed end guide tool 9. Back muscle tissueseparates easily here to allow the upper insertion of the rod 4 and canbe further separated by finger separation or cutting through one of theincisions 165, if required.

After initial insertion, the second end 42 of the rod 4 is positioned inthe channel 34 of the end guide tool 9 that is located next to theinsertion point of the rod 4, as is seen in FIG. 14.

Once the rod 4 is positioned in the guide tools 9 and 10, a pusher tool136 of the type shown in FIG. 16 is utilized to push the rod 4 in eachguide tool 9 or 10 toward the bone screw 6 associated with the guidetool 9 or 10 until the rod 4 is in approximately the position seen inFIG. 15. During this time, the end guide tools 9 can be manipulated tohelp movement of the rod 4 therealong and can especially have the topsthereof splayed outwardly relative to each other, as seen in FIG. 15.Again, the flexibility of the skin 14 allows such manipulation. Once therod 4 reaches the bottom 39 of the end guide tools 9, the rod ends 42encounter the cut outs 45 on either side of the rod 4 and passtherethrough. The rod 4 is sized to extend a little beyond each end bonescrew 6 to ensure full capture and reduce likelihood of dislodgement.Because the channels 34 are slightly inward of the full outer length ofthe rod 4, the channels 34 must be tilted outward somewhat as seen inFIG. 15 to allow the rod 4 to pass down the channels 34 or one end 42must be driven downward before the other. When the rod 4 is at thebottom of the guide tools 9 and 10, such as seen in FIG. 19, the endguide tools 9 can be returned to a position that is appropriate forproperly aligning the bone screw heads 6 relative to the rod 4 prior totightening and torquing the closure tops 52. Because the rod 4 isnormally bent and/or the vertebrae 18 do not align properly, the rod 4must normally be biased into the bone screw heads 6. This isaccomplished by using the closure installation tool 145 in the mannerillustrated on the right hand side in FIG. 16 and in FIG. 17.

In particular, the tool 145 has a socket 148 that grips the break offhead 127 of the closure top 52. The installation tool 145 with closuretop 52 therein is placed in the elongate top to bottom channelassociated with the guide tools 9 and 10 either by entry from the sidesuch as into channel 25 through opening 26 in guide tool 9 or intochannel 25 through the top end 38 of the guide tool 9. The closure top52 is then driven under manual control of the surgeon by use of theinstallation tool 145 toward the rod 4. Near the bottom of the guidetools 9 and 10, such as near the bottom 39 of end guide tool 9, theclosure top 52 engages the helical wound first guide and advancementstructure 50 and the tool 145 and closure top 52 are rotated mate theclosure top helical mating structure 125 with the first guide andadvancement structure 50 so as to drive the closure top 52 downwardagainst the rod 4 and to urge the rod 4 downward into the bone screwchannel 67. At the bottom of the guide tool 9 or 10, the closure topmating structure 125 engages and begins to mate with the guide andadvancement structure 76 on a respective bone screw 6 and continuedrotation of the tool 145 drives the rod 4 downward and into engagementwith the dome 71 of the bone screw shank 60, so as to snug against andfrictionally lock the shank 60 in position relative to the bone screwhead 66, see FIG. 18.

Once all of the closure tops 52 are in final seating position inrespective bone screws 6 and the surgeon is satisfied with the positionof all of the elements, such as is seen in FIG. 19, the antitorque tool153 is mounted over each guide tool 9 or 10, as shown in FIG. 21 withthe bridges 158 straddling the rod 4 to prevent rotation. Theinstallation tool 145 is inserted in the associated guide tool 9 or 10and engaged with the break off head 127. By cooperative use of the tools145 and 153 a preselected torque is manually applied to the break offhead 127 and it breaks from the closure top body 123 in the manner shownin FIG. 22 and is removed along with the antitorque tool 153.

The guide tools 9 and 10 are then each rotated ninety degrees to alignthe attachment structure, such as structures 55 and 113 with the openingbetween bone screw arms 74 and 75, as shown in FIG. 23, so that therecess 49 straddles the rod 4 to allow the attachment structure 55 or113 to disengage from the receiver 78. The guide tool 9 or 10 is thenpulled axially upward away from the bone screw 6 and from the incision165 in the skin 14, after which the incision 165 is closed.

It is to be understood that while certain forms of the present inventionhave been illustrated and described herein, it is not to be limited tothe specific forms or arrangement of parts described and shown.

1. A guide tool for implanting a spinal rod in a patient wherein: a)said guide tool being non-integral with and adapted to be selectivelyand removably joinably attached at a lower end thereof to a spinalimplant bone screw; b) said guide tool including a longitudinal channelwith a central axis extending upwardly from said lower end thereof; saidchannel being sized and shaped to be adapted to receive the rodlaterally positioned with respect to the axis of the channel foroperably guiding the rod from a position exterior of the bone screwtoward and into the bone screw; c) said guide tool having a helicallywound first guide and advancement structure located near a bottomthereof; d) said first guide and advancement structure providing ahelical pathway adapted to rotatably and matingly receive a matingstructure of a bone screw closure top; and f) said first guide andadvancement structure also being adapted to be aligned during removableattachment of the tool with the bone screw with a second guide andadvancement structure on such bone screw so as to continue said helicalpathway when the guide tool is joined with such the bone screw; theguide tool being elongate and being sized and shaped to extend outsidethe patient when the guide tool is attached to the bone screw so as tobe adapted to transfer the closure top between the guide tool and thebone screw upon rotation of the closure top.